Multi-scale scanning tunneling microscopy imaging of self-organized regioregular poly(3-hexylthiophene) films

Two-dimensional self-organized poly(3-hexylthiophene) films on highly oriented pyrolytic graphite have been probed at the solid/substrate interface by scanning tunneling microscopy (STM). Structural morphology and typical polymer conformations are visualized and discussed from mesoscopic to nanoscopic scales, including mesoscopic assembly of polycrystals, crystalline monodomain orientations and sizes, grain boundaries, chain folds, and other conformational features. STM estimation of the average chain length is in remarkably good agreement with that derived from size-exclusion chromatography. The multiscale analysis supports a picture where heterogeneities exist at different length scales.